The life sciences community at Brandeis University has active research programs in diverse areas of the biological sciences including immunology, neuroscience and developmental biology. As a large core group of researchers in these fields, we have been brought together by our mutual need for an essential new piece of equipment, a flow cytometer with sorting capabilities (FACS). This instrument will be used in many applications that require the analysis of cell populations based on parameters of size, DNA content, and the presence and density of specific cell surface molecules. The separation and isolation of limited numbers of fluorescent-tagged cells will provide material for a number of studies involving functional and molecular analyses of subpopulation of cells. Following consultation with other members of the Boston-area scientific community, we have concluded that the FACSCaliburtm instrument from Becton-Dickinson best suits our needs. This instrument will fill a major gap in the resources available for scientific research at Brandeis University, and will permit us to carry out a number of studies on the cellular and molecular basis of biological processes. The core user group has several long-term goals: 1) to understand the function and development of humoral and cellular immunity, 2) the control of cell fate decisions and function of cell surface receptors and channels in the nervous system, 3) the regulation of the cell cycle in yeast and packaging of DNA in germ cells, and 4) the role of tyrosine kinases in mammalian development and leukemogenesis. The outcomes of these studies will have broad relevance to human disease in areas that include the development of new models for vaccination and transport of maternal immunity, and an understanding of the mechanisms of carcinogenesis by the activation of cellular oncogenes and genetic recombination. In addition, studies of the molecules responsible for the development and maintenance of the nervous system will shed light on the defects leading to neurodegenerative diseases.